Add-a-leafs will stiffen yup your ride, but not unbearable unless you drive on a lot of bad roads, its actually good for road handling, except bad roads again. I had the 1 5/8" f-150 spring seats (spacers) in the front and both add-a-leaf and shackles in the back. The back was slighty higher, I got about an inch each out of the shackles and 1.5" from the add-a-leaf. This will vary with spring condition. For both spacers and coils in the front you will need a camber kit if you don't have one, and even then you'll probably need a different one(cams). You can't go more than 2" with out getting drop brackets. Spacers or coils is a matter of budget and purpose. If its just for looks the f-150 seats or the spacers in the kit on ebay will be fine. New springs might ride nicer and will probably flex a little more, but not much, especially if they are stiffer.